Environmental determinants of health are increasingly recognized across the life course, yet they remain insufficiently integrated into routine clinical reasoning. This opinion paper examines why environmental risk often remains peripheral in patient care despite growing evidence of its relevance to disease susceptibility, progression, and prevention. It argues that this gap reflects not only the incomplete translation of environmental health research into clinical practice, but also structural features of clinical reasoning that favor immediate actionability, discrete disease mechanisms, measurable thresholds, and close temporal links between exposure and disease. This pattern is described here as exposure-blind medicine: a structural tendency for environmental contributors to remain under-recognized in diagnostic and management pathways unless they are acute, obvious, or readily actionable. The paper discusses the clinical consequences of this pattern and outlines a pragmatic approach for more selective integration of environmental context into patient care. Reframing environmental exposure as a context-dependent but clinically relevant component of routine reasoning may support a more complete and scientifically aligned model of care.
Abstract Heavy metal contamination in drinking water is a public health issue. This study conducted a probabilistic meta-analysis of health risk assessment for six commonly reported heavy metals (arsenic [As], lead [Pb], mercury [Hg], cadmium [Cd], chromium [Cr] and nickel [Ni]) in drinking water across six continents (Asia, Europe, Africa, North America, South America and Oceania) using the data from 2000 to 2024. Human exposure and risks were quantified in terms of cancer risks (CRs) and loss of disability-adjusted life years (DALYs). Monte Carlo simulation was employed to generate 5,000 random scenarios to incorporate uncertainty in risk assessment. Africa exhibited the average concentrations of As, Pb, Hg, Cd, Cr and Ni in drinking water of 176.7, 123.3, 93.7, 80.2, 91.0 and 35.1 μg/L respectively. The overall averages of CRs in Asia, Europe, North America, South America, Africa and Oceania were predicted to be 3.25 × 10 −4 , 1.34 × 10 −4 , 2.26 × 10 −4 , 1.18 × 10 −3 , 4.1 × 10 −3 and 5.83 × 10 −5 respectively while the DALYs were 1.48 × 10 5 , 7.14 × 10 3 , 1.20 × 10 4 , 5.51 × 10 4 , 8.63 × 10 5 and 2.68 × 10 2 respectively. Across six continents, inorganic fraction of arsenic (iAs) was the dominant carcinogen, contributing (45–91) % to total cancer risks in Asia, contributions of iAs and Cd were almost similar. The loss of DALYs were highest in Africa (8.63 × 10 5 ), due mainly to arsenic-induced bladder and cadmium-induced lung cancers. The global economic burden was USD 29 billion, with Africa accounting for almost 52 %. Sensitivity analysis identified iAs as the key parameter. The heavy metal contamination is a public health issue that requires decisive actions in Africa, South America and Asia.
Abstract Background and aims Autism Spectrum Disorder (ASD) is a multifaceted neurodevelopmental condition shaped by genetic, environmental, and biochemical influences. Among these, trace elements such as zinc (Zn) and copper (Cu) have attracted considerable interest due to their involvement in synaptic transmission, antioxidant defense mechanisms, and neuroinflammatory processes. This systematic review and meta-analysis aimed to assess whole blood, serum and plasma levels of Zn and Cu in children diagnosed with ASD compared to neurotypical controls. Methods A comprehensive literature search was conducted in accordance with PRISMA guidelines across PubMed, Embase, Web of Science, and Scopus databases up to July 2025. Eligible studies included observational studies, including cross-sectional and case–control studies reporting whole blood, serum, or plasma concentrations of Zn and Cu in children with ASD. Two independent reviewers performed study selection and data extraction, and quality assessment using the modified Newcastle–Ottawa Scale (NOS). Meta-analyses were conducted using STATA version 17.0. Pooled effect sizes were calculated using Hedges’s g. Heterogeneity was evaluated using the I 2 statistic, and publication bias was assessed via funnel plots and Egger’s test. Results In total 15 studies comprising 2,537 participants (849 children with ASD and 1,688 controls) met the inclusion criteria. The meta-analysis revealed non-significant pooled differences between children with ASD and controls for Zn (SMD=−0.48, 95 % CI: −1.08 to 0.13; p=0.13) and Cu (SMD=−0.59, 95 % CI: −1.30 to 0.11; p=0.10). Substantial heterogeneity (I 2 >97 %) was observed for both analyses. Conclusions The children with ASD and the control groups did not significantly differ in blood Zn or Cu levels. Due to the possibility of publication bias and heterogeneity that existed between included studies, the results should be interpreted cautiously. Thus, existing evidence should be treated as an attempt to generate the hypothesis, and higher-quality studies are needed to uncover the role of trace elements homeostasis in ASD.
Abstract Herbal medicine products (HMPs) are widely consumed worldwide, yet contamination with toxicants such as heavy metals poses potential environmental health and consumer safety concerns. This study systematically reviewed studies measuring contamination levels of lead (Pb), cadmium (Cd), mercury (Hg), or arsenic (As) in crude herbal materials and formulated HMPs. PubMed, Scopus, Web of Science, and CINAHL were searched from inception to June 2026. Random-effects meta-analyses estimated metal-specific pooled mean concentrations; moderator analyses and meta-regression explored heterogeneity. Seventy studies from 27 countries or territories were included. Forty-eight, 45, 25, and 35 studies contributed to the Pb, Cd, Hg, and As meta-analyses, respectively. Pooled concentrations in HMPs were 1.930 mg/kg (95 % CI: 0.993–2.860) for Pb, 0.206 mg/kg (95 % CI: 0.142–0.270) for Cd, 0.122 mg/kg (95 % CI: 0.016–0.228) for Hg, and 0.501 mg/kg (95 % CI: 0.267–0.736) for As; heterogeneity was considerable for all metals. Pb concentrations differed by national income group (p=0.007), and Cd concentrations differed by product classification (p=0.002), with higher Cd concentrations in crude materials than formulated products. Higher gross national income per capita was associated with lower Pb and As concentrations. Reported exceedance of study-specific comparators was common but varied substantially because regulatory limits, product categories, and denominators differed across studies. Heavy metal contamination of HMPs varies between settings and products, which underscores the need for strengthened quality surveillance, improved monitoring, and harmonized regulatory standards.
The rising prevalence of cognitive decline and dementia imposes substantial burdens on individuals, families, and society. Air pollution has increasingly been linked to adverse cognitive outcomes, but findings vary across pollutants, study designs, and exposure-assessment methods. This review summarizes epidemiological evidence on ambient air pollution and cognitive outcomes among older adults, identifies research gaps, and outlines priorities for future investigation. PubMed was searched through February 2025 for peer-reviewed, English-language observational studies published from January 2000 onward that examined ambient air pollution and cognitive outcomes among adults aged 50 years and older. A total of 36 studies met the inclusion criteria. Fine particulate matter (PM2.5) was the most frequently studied pollutant, and most studies reported associations between higher PM2.5 exposure and poorer global or domain-specific cognitive function, faster cognitive decline, or increased risk of cognitive impairment and dementia. Evidence for other pollutants generally suggested adverse associations, although ozone (O3) findings were the most inconsistent. Differences in exposure assessment methods, cognitive assessment, study designs, confounding control, and population susceptibility likely contributed to heterogeneity. Overall, the accumulated evidence suggests that long-term ambient air pollution exposures may contribute to poorer cognitive outcomes in later life. These findings underscore the importance of strengthening air quality standards to protect brain health and developing targeted interventions for vulnerable older populations.
